1. Technical Field
The present invention relates to a light output apparatus and a method for manufacturing the light output apparatus.
2. Related Art
There is a known coordinate input apparatus of related art that detects a position pointed with a finger or a pointing device (pointing stick, for example) operated within a coordinate input region set in advance. A known example of a coordinate input apparatus of this type forms a light (infrared light) layer on and along a display surface on which an image is displayed and detects a position where light is reflected off a pointing device as a pointed position (see Japanese Patent No. 4,478,559, for example).
The coordinate input apparatus described in Japanese Patent No. 4,478,559 includes a flat-surface input section formed of a display device, a left coordinate sensor unit and a right coordinate sensor unit disposed in positions in the vicinity of opposite ends of the input section, a retroreflector member provided around the input section, and a control unit. Each of the sensor units has a coordinate detection light projector and a coordinate detection light receiver. The coordinate detection light projector is formed of an infrared LED (light emitting diode) that emits infrared light and a projection lens that projects the infrared light in the form of a light flux having a shape limited in the upward/downward direction within a horizontal angular range. The coordinate detection light projector outputs the infrared light toward the input section to form a thin infrared light layer over the input section.
When an operator uses a pointing device to perform operation on the input section, a finger or the pointing device blocks part of the light projected from the coordinate detection light projectors described above, and the optical intensity therefore decreases only in the blocked portion. As a result, in the coordinate input apparatus described above, each of the coordinate detection light receivers detects a range on the input section where the light intensity distribution changes, and the control unit calculates the coordinates of the pointed position described above.
It is conceivable to integrate the right coordinate sensor unit and the left coordinate sensor unit described in Japanese Patent No. 4,478,559 with each other into a single unit for simplification of the configuration and arrangement of the unit.
On the other hand, an infrared LED, which is a heat generator but sensitive to heat, needs to be cooled. It is therefore conceivable to provide a heat dissipation member so connected to each of the infrared LEDs in a heat conductive manner and allow the heat dissipates to dissipate the heat generated by the corresponding infrared LED.
To this end, the following configuration has been proposed: A plurality of sensor units each including a solid-state light source, such as an infrared LED, a parallelizing lens that parallelizes light from the solid-state light source, and a diffusing lens (Powell lens, for example) that diffuses the parallelized light form a light output apparatus, and in each of the sensor units, the positions of the solid-state light source and the diffusing lens are adjusted with respect to the parallelizing lens and the solid-state light source is connected to a heat sink in a heat conductive manner.
In the configuration described above, however, in which the position of the solid-state light source is adjusted with respect to the parallelizing lens, a fixture that grasps the solid-state light source for the positional, adjustment needs to be disposed on the side facing away from the light exiting side of the solid-state light source. The configuration has a problem of insufficient space where a relatively large heat sink is provided. Further, after the position of each of the solid-state light sources is adjusted, it is necessary to connect a heat sink to each of the solid-state light sources. Each of the solid-state light sources therefore needs to foe provided with an individual heat sink, undesirably resulting in an increase in the number of parts and limited cooling efficiency.